How many people have COVID-19 and don’t even know it?

The proportion of people who are asymptomatic matters hugely because of the implications for the mortality rate and infection rate of the general population. We know that the cases which are being recorded are only the tip of an iceberg – since the UK moved into the ‘delay’ phase a couple of weeks ago we are no longer even testing people unless they present at hospital with severe symptoms. What we don’t know is how large that iceberg is. If it is as big as claimed by modeling by an Oxford team led by Professor Sunetra Gupta — which suggested that up to half the UK population could already be infected — then there may be no point in locking down Britain or any other country: COVID-19 is a chronic disease which has already spread through the population but will be of limited concern because it is not very deadly.

That is the point made by Tom Jefferson and Carl Heneghen of Oxford University’s Centre for Evidence-Based Medicine, who did not mince their words when they wrote on the center’s website last Monday: ‘Lockdown is going to bankrupt all of us and our descendants and is unlikely at this point to slow or halt viral circulation as the genie is out of the bottle. What the current situation boils down to is this: is economic meltdown a price worth paying to halt or delay what is already amongst us?’

In reaction to the latest data from China, Jefferson goes even further. Noting that the data sample is very small, and thus there is room for some doubt, he tells the BMJ: ‘And even if they are 10 percent out, then this suggests the virus is everywhere. If — and I stress, if — the results are representative, then we have to ask, “What the hell are we locking down for?”’